试想如果我们通过拉拽电灯开关就可以轻松控制基因的表达,这将是一件多么神奇的事情;近日,来自北卡罗来纳大学的研究者成功运用了光敏分子来控制基因的表达,研究者的这种方法可以高精度地研究基因的功能,而且对于诸如癌症等疾病可以开展靶向治疗。
三股螺旋形式的寡核苷酸类(TFOs)分子通常通过结合在双股DNA上来阻止基因的转录,研究者Alex Deiters试图找到一种更为精准的方法来控制TFOs,并且使得控制的范围延伸至特定基因的转录。因此研究者设计了一种光敏支架来吸附到TFO上,当这种光敏支架暴露于紫外光下就会移动,此时,TFO便可以自由结合在DNA上,抑制特定基因的转录。
如果没有光的话,基因的转录活性为100%,但是,一旦有光的话,研究者就可以使得目的基因的转录效率降至25%,这对于基因的表达量来说是一个明显的降低。
此外,研究者Deiters优化了光敏支架吸附到TFO上的过程,在没有紫外线的时候,TFO行使正常功能,可以结合至DNA上抑制基因的表达;当暴露在紫外线下后,光敏支架抑制TFO,阻止TFO结合在DNA上,最终开启基因的表达。
研究者表示,他们开发出的这种通过光敏开关来控制基因的遗传转录的方法给很多科学家研究基因功能带来了便利,可以让科学家更为立体的控制基因的表达,这样一来,我们不管在什么环境中都可以对特定基因的功能进行研究学习。
这项研究成果刊登在了近日的国际杂志ACS Chemical Biology上,研究经费由国立卫生研究院支持。(生物谷:T.Shen编译)
doi:10.1021/cb300161r
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PMID:
Regulation of Transcription through Light-Activation and Light-Deactivation of Triplex-Forming Oligonucleotides in Mammalian Cells
Jeane Govan, Rajendra Uprety, James Hemphill, Mark O. Lively, and Alexander Deiters
Triplex-forming oligonucleotides (TFOs) are efficient tools to regulate gene expression through the inhibition of transcription. Here, nucleobase-caging technology was applied to the first temporal regulation of transcription through light-activated TFOs. Through site-specific incorporation of caged thymidine nucleotides, the TFO:DNA triplex formation is blocked, rendering the TFO inactive. However, after a brief UV irradiation, the caging groups are removed, activating the TFO, and leading to the inhibition of gene transcription. Furthermore, the synthesis and site-specific incorporation of caged deoxycytidine nucleotides within TFO inhibitor sequences was developed, and allows for the light-deactivation of TFO function and thus photochemical activation of gene expression. After UV-induced removal of the caging groups, the TFO forms a DNA dumbbell structure, rendering it inactive, releasing it from the DNA, and activating transcription. These are the first examples of light-regulated TFOs and their application in the photochemical activation and deactivation of gene expression. In addition, hairpin loop structures were found to significantly increase the efficacy of phosphodiester DNA-based TFOs in tissue culture